Uplink grant, downlink assignment and search space method and apparatus in carrier aggregation

Abstract

Methods of mapping, indicating, encoding and transmitting uplink (UL) grants and downlink (DL) assignments for wireless communications for carrier aggregation are disclosed. Methods to encode and transmit DL assignments and UL grants and map and indicate the DL assignments to DL component carriers and UL grants to UL component carriers are described. Methods include specifying the mapping rules for DL component carriers that transmit DL assignment and DL component carriers that receive physical downlink shared channel (PDSCH), and mapping rules for DL component carriers that transmit UL grants and UL component carriers that transit physical uplink shared channel (PUSCH) when using separate coding/separate transmission schemes.

What is claimed is: 
     
       1. A method performed by a wireless transmit receive unit (WTRU) for decoding information related to cross-carrier scheduling, the method comprising:
 monitoring at least one WTRU-specific search space on a first component carrier for a set of physical downlink control channel (PDCCH) candidates, wherein the at least one WTRU-specific search space includes at least a first control channel element (CCE) and at least a second CCE; 
 decoding a first PDCCH candidate and a second PDCCH candidate received via the first component carrier using a predetermined identifier of the WTRU, wherein the decoding the second PDCCH candidate includes decoding a DCI format including a carrier indicator, wherein the first PDCCH candidate is detected on the at least first CCE and the second PDCCH candidate is detected on the at least second CCE; 
 determining a second component carrier based on the carrier indicator; 
 receiving a first physical downlink shared channel (PDSCH) via the first component carrier; and 
 receiving a second PDSCH via the second component carrier, wherein the second PDSCH is received without monitoring a PDCCH on the second component carrier. 
 
     
     
       2. The method of  claim 1 , wherein the WTRU is not required to monitor the PDCCH on the second component carrier responsive to the carrier indicator indicating the second component carrier. 
     
     
       3. The method of  claim 1 , wherein a position of the at least second CCE within the at least one WTRU-specific search space corresponds to a CCE number. 
     
     
       4. The method of  claim 3 , wherein the CCE number maps to the second component carrier that is indicated by the carrier indicator. 
     
     
       5. The method of  claim 1 , further comprising monitoring at least a second WTRU-specific search space including at least a third CCE and at least a fourth CCE on a third component carrier for a second set of PDCCH candidates. 
     
     
       6. The method of  claim 5 , further comprising decoding a third PDCCH candidate and a fourth PDCCH candidate received via the third component carrier using the predetermined identifier of the WTRU, wherein the decoding the fourth PDCCH candidate includes decoding a second DCI format including a second carrier indicator and wherein the third PDCCH is detected on the at least third CCE and the fourth PDCCH candidate is detected on the at least fourth CCE. 
     
     
       7. The method of  claim 6 , further comprising:
 determining a fourth component carrier based on the second carrier indicator, the fourth component carrier carrying a fourth PDSCH; 
 receiving a third PDSCH via the third component carrier; and 
 receiving the fourth PDSCH via the fourth component carrier, wherein the fourth PDSCH is received without monitoring a PDCCH on the fourth component carrier. 
 
     
     
       8. The method of  claim 1 , wherein the first PDCCH candidate is received via the at least first CCE at a first particular aggregation level and the second PDCCH candidate is received via the at least second CCE at a second particular aggregation level. 
     
     
       9. The method of  claim 8 , wherein the first particular aggregation level is the same as the second particular aggregation level. 
     
     
       10. A wireless transmit receive unit (WTRU) capable of decoding information related to cross-carrier scheduling, the WTRU comprising:
 circuitry configured to monitor at least one WTRU-specific search space on a first component carrier for a set of physical downlink control channel (PDCCH) candidates, wherein the at least one WTRU-specific search space includes at least a first control channel element (CCE) and at least a second CCE; 
 the circuitry further configured to decode a first PDCCH candidate and a second PDCCH candidate received via the first component carrier using a predetermined identifier of the WTRU, wherein a DCI format including a carrier indicator is decoded on the first PDCCH, wherein the first PDCCH candidate is detected on the at least first CCE and the second PDCCH candidate is detected on the at least second CCE; 
 the circuitry further configured to determine a second component carrier based on the carrier indicator; 
 the circuitry further configured to receive a first physical downlink shared channel (PDSCH) via the first component carrier; and 
 the circuitry further configured to receive a second PDSCH via the second component carrier, wherein the second PDSCH is received without monitoring a PDCCH on the second component carrier. 
 
     
     
       11. The WTRU of  claim 10 , wherein the WTRU is not required to monitor the PDCCH on the second component carrier responsive to the carrier indicator indicating the second component carrier. 
     
     
       12. The WTRU of  claim 10 , wherein a position of the at least second CCE within the at least one WTRU-specific search space corresponds to a CCE number. 
     
     
       13. The WTRU of  claim 12 , wherein the CCE number maps to the second component carrier that is indicated by the carrier indicator. 
     
     
       14. The WTRU of  claim 10 , wherein the circuitry is further configured to monitor at least a second WTRU-specific search space including at least a third CCE and at least a fourth CCE on a third component carrier for a second set of PDCCH candidates. 
     
     
       15. The WTRU of  claim 14 , wherein the circuitry is further configured to decode a third PDCCH candidate and a fourth PDCCH candidate received via the third component carrier using the predetermined identifier of the WTRU, wherein a second DCI format including a second carrier indicator is decoded on the fourth PDCCH and wherein the third PDCCH is detected on the at least third CCE and the fourth PDCCH candidate is detected on the at least fourth CCE. 
     
     
       16. The WTRU of  claim 15 , the circuitry further configured to:
 determine a fourth component carrier based on the second carrier indicator, the fourth component carrier carrying a fourth PDSCH; 
 receive a third PDSCH via the third component carrier; and 
 receive the fourth PDSCH via the fourth component carrier, wherein the fourth PDSCH is received without monitoring a PDCCH on the fourth component carrier. 
 
     
     
       17. The WTRU of  claim 10 , wherein the first PDCCH candidate is received via the at least first CCE at a first particular aggregation level and the second PDCCH candidate is received via the at least second CCE at a second particular aggregation level. 
     
     
       18. The WTRU of  claim 17 , wherein the first particular aggregation level is the same as the second particular aggregation level.